Rheostat



Nov. 22, 1927.

A. J. CARTER mmosn Filed June 25. 1926 Patented Nov. 22, 1927.

UNITED STATES y 1,650,008 PATENT oEEicE.

ALVA J'. CARTER, OF CHICAGO, ILLINOIS, ASSIGNOR T0 CARTER RADIO COMPANY, OF CHICAGO, ILLINOIS, A CORPORATION F ILLINOIS.

RHEOSTAT.

v Application led June 25,

My invention relates to rheostats and more.

' particularly to rheostats of the character'in which an annular resistor is employed which is mounted upon a suitable base and with which a rotatable control element cooperates."

It is an object of my invention to simplify the construction of devices of this character by so arranging the construction that the support for the resistor may be made of one piece.

My invention further contemplates other simplifications in the construction Aof devices of this character and also has other objects, all of which will more clearly appear from the description of one form of the invention which I will now give in connection with the accompanying drawing in which- Fig. 1 is a bottom view of a device constructed in accordance with my invention;

Fig. 2 is a viewon line 2-2 of Fig. 1; Fig. 3 is a Jfragmentary view on line 3-3 of Fig. 1; and

Fig. 4 is a fragmentary view on line 4-4 of Fig. 1.

Referring to the drawings, I show a panel 10 upon which my device may be suitably mounted. The device itself consists of a bushing or supporting element 11 which is screw-threaded as shown and which is adapted to cooperate with the nut 12 to suitably hold the device in place upon the panel. shaft 13 is rotatably mounted in the bushing and carries a linger piece 14: suitably `fastened thereto by the set screw 15 through the agency of which the shaft 13 may be rotated for a purpose presently to be explained. l

The bushing 11 has suitably clamped to it a4 supporting plate .16, which supporting plate is shown as being slightly dished and which is so formed at its extremities as'to present a U-shaped structure as shown at 17. The shaft 13 carries a contact linger 18, which contact finger is firmly'secured in position upon the shaft 13 by the nut 19 in4 cooperation with the shoulder hub portion 21, which hub portion has a plurality of contact fingers 22 punched downwardly therefrom which engage with the flat end surface of the bushing 11, thus to establish a firm rubbing contact between these two elements and thus indirectly between the fino'er 18 and the plate 16.

he U-shaped portion 17 of the plate 16 1926. Serial No. 118,475.

is adapted to support and firmly hold in position the resistor 28. This resistor consists of the insulating strip 24 about which a length of` wire 25 is helically wound so as to cooperate with the contact linger 18. This resistor is partially encircled by a strip of insulation 26 which is bent U-shaped to conform to the outline of the element 17. The parts thus described, that is, the U-shaped element 17, together with the insulating strip .26 'and together with the resistor 23 are then mounted in a suitable press so that the two legs of the U-shaped element 17 are pressed toward one another, thus to hold all of the parts lirmly in position. One extremity of the wire 25 is electrically connected to the contact element 27 which has a downwardly and laterallyl extending Contact strip 28 which engages the said extremity ofthe .resistance wire 25. This is more clearly shown inFig. 2.

It will be` noted that the wire 25 stops a short distance away from this contact terminal 27 as shown in Fig. 1 so thatwhen the contact finger 18 is swung to its limiting position in a counter-clockwise direction against the stop 29, presently to be explained, that this contact linger then does not engage the wire. A second Contact terminal 30 is provided which is electrically connected with the plate 16. This terminal is similar to terminal 27, and has also a downwardly and laterally extending contact strip 31 shown more clearly in Fig. 4. Thus it will ybe seen that as the contact finger 18 is rotated clockwise from the position shown in Fig. 1, that more of the resistance wire 25 is included in the circuit between the Contact elements 27 and 30. .a

It will be noted that the provision oft-he downwardly and laterally extended portions on` the contacts 27 and'30, whereby they are gripped in position by the U-shaped portion 17, insuresa very simple means of attaching the contacts. This does away with the ne* cessity ofusing screws or other means of fastening the contacts and materially reduces the cost of construction.

A further novel feature of my, invention 105 same time provides means which serve as a stop to limit the movements of the contact finger 18.

From what has thus been described, the

n nature yof my invention will be readily apparent to those skilled in the art and having thus described one form which' my invention may take, what I claim as new and desire to claim by Letters Patent is:

1. A device of the character described comprising an annular resistor element, a metallic U-shaped support element therefor, insulation between said element and said support, said U-shaped element being compressed to hold the entire structure firmly together, a support to which said U-shaped element is attached, a contact element mounted uponsaid support concentrically with saidresistor for movement over said resistor and a stop projecting upwardly into the path of said contact element from said U- shaped support. s

2. A device of the character described comprising an annular resistor element, a hub, a U-shaped support member for said resistor element having means whereby it is attached to said hub and a contact element mounted upon said hubfor cooperation with said resistor, said support member having a projection struck upwardly therefrom into' the path of said contact element.

3. A device of the character described coniprising a resistor` element, a support therefor, insulation between said element and said support, and a contact element having a portion extending downwardly between said insulation and said resistor element, said support being compressed vto hold the entire structure together. i v y 4I A device of the character described comprising a resistor element, a support therefor, insulation between said element and said support, and a contact element having a portion extending downwardly between said insulation and said resistor element and bent laterally beneath theresistor element, said support being compresed to hold the entire structure together.

5. A device of the character described coinprising a resistor element. a support therefor, insulation between said element and said support, and a contact element having a portion extending downwardly between said insulation and said support, said support being compressed to hold the entire structure together.

6. A device of the character described comprising a resistor element, a U-shaped support therefor, insulation between said element and said support and a contact element having a portion extending between said support and said insulation, the end of said portion being bent laterally along the interior of the U-shaped support, said U-shaped support being compressed to hold the entire structure together.

7. A device of the character described comprising an annular resistor element, an annular U-shaped insulation strip in which said element is seated and means for supporting said strip and element and clamping them firmly together comprising a circular metallic disk having the outer rim portion thereof bent to forman annular recess in which said strip is clamped.

8. A device of the character described comprising an annular resistor element, an annular U-sliaped insulation strip in which said element is seated and means for supporting said strip and element and clamping them firmly together comprising a circular metallic disk having the outer rim portion thereof bent to form an annular recess in which said strip is clamped, and contact terminals clamped between said rim portion and strip and between said strip and resistor element.

9. A device of the character described comprising an annular resistor element, means for supporting said element comprising a disk having a portion thereof bent to form an annular recess in which said element is clamped, and a hub for said disk having means for mounting the same upon a panel with said recess facing away from the panel.

10.'A device of the character described comprising an annular resistor element. means for supporting said element comprising a metallic disk having a portion thereof bent to form an annular recess in which vsaid element is clamped and insulating means insulating said element from said disk.

In witness whereof, I hereunto subscribe my name Ithis 9th day of June A. D., 1926.

ALVA J. CARTER. 

